Charge forming apparatus



Oct. l0, 1961 B. c. PHILLIPS 3,003,754

CHARGE FORMING APPARATUS Filed Dec. 16, 1958 4 Sheets-Sheet 1 INVENTOR I.BERNARD @PHILLIPS 'ATTORNEY Oct. 10, 1961 B. c. PHILLIPS 3,003,754

CHARGE FORMING APPARATUS Filed Dec. 16, 1958 4 Sheets-Sheet 2 INVENTOR I.BERNARD LPHJLLIPS.

BY j @ATTORNEY Wr Alim,

Oct. 10, 1961 B. c. PHILLIPS l 3,003,754

CHARGE FORMING APPARATUS Filed Dec. 16, 1958 4 Sheets-Sheet 3 TTORNEYOct. 10, 1961 B. c. PHILLIPS 3,003,754

CHARGE FORMING APPARATUS Filed Dec. 16, 1958 4 Sheets-Sheet 4 tivi-.

lNVENTORI BERNARD L". PHILLIPS.

M QTTORNEY United States Patent iiice 3,605,754 CHARGE FGRMING APPARATUSBernard C. Phillips, Ioledo, Ohio, assignor to The TillotsonManufacturing Company, Toledo, Ohio, a corporation of Ohio Filed Dee.16, 1958, Ser. No. 780,845 2 Claims. (Cl. 261'37) lhis invention relatesto charge forming' devices or ap'- paratus for use with internalcombustion engines and 'more' especially to apparatus for forming a fuelvand air mixture wherein the fuel constituent is delivered into the airin a mixing passage solely by aspiration or differential pressureestablished through engine operation.

Internal combustin engines of bth the Slo-called two cycle and fourcycle types are being utilized extensively for powering chain saws, lawnmowers, small boats, and for various other purposes. In certain uses,for example, in powering chain saws the engine and the charge formingAvdevice are sometimes tilted to extreme angular and ofttimes invertedpositions. The conventional type of charge forim'ng device that has beenin use for many years embodies a iloat actuated fuel control means andsuch charge forming devices are' not satisfactory for use with engineswhich are to be operated in extreme angular positionsnd cannot beutilized at all for powering chain saws where the saws must be capableof use in inverted positions;

Diaphragm carburetors have been developed which are adaptable foroperation' in extreme angular o' inverted positions, and diaphragmcontrolled carburetors or charge forming devices embody some form ofmeans to prevent or minimize flooding o r excess delivery of fuel intothe mixing passage when the charge forming device or carburetor is in anextreme angular or inverted position. One form of means for preventingilooding of fuel into the mixing passage is disclosed in my Patent2,733,902, granted February 7, 1956, which arrangement embodies" a ballcheck means inthe region of the main fuel discharge into the mixingpassage which, upon inversion of the charge forming device, interruptsor blocks the ow of fuel into the mixing passage through a main fueldischarge. Another method of avoiding ooding of fuel into the mixingpassage upon extreme angular or inverted movements or positions of thecarburetor or charge forming device forms the subject matter of myPatent 2,841,372, granted on July l, 1958. The arrangements in thislatter patent utilizes capillary characteristics" of the' fuel forestablishing a fluid seal or block to avoid ooding`cond' tions when thecarburetor or charge forming device is'v utilized in an extreme angularor inverted position;

The present invention embraces a simple but effective means foradjustably metering or varyingl the fuel delivered into the mixingpassage as the speed of the engine with which the device is used isincreased or decreased and for' restricting fuel flow to the mixingpassage under idling or low speed conditions of the engine with Whichthe apparatus is used whereby excess delivery of fuel or flooding of themixing passage is eliminated.

An object of the invention resides in' a' charge forming apparatus ofthe diaphragm type wherein fuel is delivered into the mixing passagesolely by aspiration or ditfere'ntial pressure established by the enginewith which the appa"-` ratus is used wherein the amount of fueladmittedto" the'` mixing' passage is metered orv regulated inaccordancewith the amount ofair moving through the mixing passage andwhereby during idling or low speed operations ofthe engine, the amountof fuel delivered into the mixing pas# sage is proportionately reduced.

Another object of the invention resides in the provision of av diaphragmtype carburetor embodying a controlled fuel metering means, the movementofwhich is correlatedwith the movement of the throttle valve toproportion- 3,003,754 Patented Qct'. 1 0,

ately inereasethe amount of fuel delivered into the ing passagedependent upon the extent of opening `of the valve and wherein the fuelmetering means is adjustable ispeet to the actuating means associatedwith the throttle valve f orinitially adjusting the relative position ofthe metering means to secure most efficient operation ofthe carburetorthroughout the operating range. Still a further object of the inventionis the provision of a diaphragm type vcarburetor embodying-,ra throttleconf trolled fuel metering means which may be successfully operated inall angular positions andin inverted position' without the delivery ofexcess fuel into the mixing passage and wherein the proportion of fueland air in the requirements of n engine with which the carburetor may beused. vFurther objects and advantages are within the scope 'f thisinvention such as relate to the arrangement, operation and function -oftli'e related elements of the structure, to various details ofconstruction and to combinations of parts, elements per se, nd toeconomies of manufacture and numerous other features as will be apparentfrom@ consideration of the spcification and drawing of a foi-mv f fileinvention, which may be preferred, in which; FIGURE 1 is a top plan viewillustrating one form of charge forming apparatus or carburetor of theinvention; FIGURE 2 is a longitudinal sectional view through thecarburetor, the `s ection being taken substantially on the linee-e2 if.FIGUR-B1;A FIGURE 3, bottom plan view of thecarburetor shwnin FIGURES 1and 2 with the diaphragm and diaphragm coverY removed and vcertainportions being shown in section for purposes of illustration;

FIGURE 4 is a transverse sectional view taken substantially on the lineof FIGURE l FIGURE 5 is a fragmentary sectional view taken substantiallyon the line o f FIGURE 2;

FIGURE 6 is a bottom plan view of a carburetor with certain partsremoved and others in section illustrating a modified form of theinvention;

FIGURE 7 is a longitudinal sectional view through the carburetor, thesection being taken substantially on the line 7-7 of FIGURE 6;

FIGURE 8 is a longitudinal sectional view taken substanti-ally on theline 8- 8 of FIGURE 6;

FIGURE 9 is a transverse sectional view taken substantially on the line9-9 of FIGURE 7;

FIGURE 10 is a bottom plan view of a carburetor embodying another formof the invention;

FIGURE ll is a longitudinal sectional view taken substantially on theline 11-11 of FIGURE l0;

FIGURE 12 is a longitudinal sectional view takenv substantially on theline 12-12 of FIGURE l0;

FIGURE 13 is a transverse sectional view taken substantially on the line13--13 of FIGURE 1l;

FIGURE 14 is a fragmentary detail sectional view takensubstantially onthe line 14-14 of FIGURE 10;# FIGURE 1 5 is a side elevational view of adiaphragm type carburetor embodying another form of the invention;

FIGURE 16 is a top plan View of the construction shown in FIGURE 15FIGURE 17 is Ha vertical sectional view through theA charge formingapparatus or carburetor, the section beingv taken substantially on theline 17 -17 of FIGUREvv 16',A

FIGURE 18 is a fragmentary sectional view taken substantiallyon the line1 8--18 of FIGURE 16;

FIGURE 19 is a fragmentary transverse sectionalview taken substantiallyon the line 19--19 of FIGURE 16,

and

FIGURE 20 is an isometric view of a fuel metering means shown in FIGUREvl7.

The charge forming apparatus or carburetor ofthe present invention isparticularly adaptable for use with either two or four cycle internalcombustion engines, such as those employed for powering lawn mowers,outboard marine engines and engines for various industrial purposes, andhas particular utility for use with two cycle engines employed fordriving chain saws where the charge forming apparatus is subjected tooperation in angular and inverted positions.

Referring to the drawings in detail, the arrangement shown in FIGURES lthrough includes a carburetor body or member formed with a mixingpassage 12 having an outlet region 14 for connection with a crankcase ofa two cycle engine or the intake manifold of a f our cycle engine. Themixing passage 12 is provided with an air inlet passage 18, a rotatableshaft 20 extending across the air inlet passage 18 and journaled insuitable bearings formed in the walls of the carburetor body 140.Mounted upon the shaft 20 is a choke valve 22 of the disk type, aportion of the shaft 20 extending exteriorly of the body 10 beingprovided with a manipulating arm 22.

Extending across the mixing passage 12 is a rotatable shaft 28 journaledin suitable bearing bosses 29 to which is secured a throttle valve 26 ofthe disk type. An end of the shaft 28 projecting exteriorly of the body10 is provided with -a manipulating arm 30. The carburetor body 10 isformed with a ange 31 provided with openings to accommodate bolts forsecuring the carburetor to the crankcase of an internal combustionengine of the two cycle type or with the intake manifold of a four cycleengine.

The carburetor body is formed with a comparatively shallow fuelreservoir or chamber 32 which is disposed as close to the mixing passage12 as possible in order to provide a minimum lift distance between thereservoir and the mixing passage. Extending across the reservoir 32 andforming a wall thereof is a flexible diaphragm or membrane 34 ofgenerally circular shape, the periphery of which engages a gasket 36. Acover 38 is disposed at the exterior face of the diaphragm having itscentral region recessed to provide a chamber 37 vented to the atmosphereby opening 39 and accommodates movement of the diaphragm.

The diaphragm 34, gasket 36 and cover 38 are held in place byperipherally spaced bolts 40'. Fuel from the chamber 32 is admitted intothe mixing passage 12 through an outlet or orifice 42 which is in directcommunication with a supplemental chamber 44 connected with the chamberor reservoir 32 in a manner hereinafter explained. The supplementalchamber 44 is closed or is esparated from the reservoir 32 by means of aWelch plug Disposed at either side of the diaphragm 34 are thin metaldisks or washers 48 and 50 for reinforcing the central portion of thediaphragm, the diaphragm and disks being held together by means of aheaded rivet 52. As shown in FIGURE 3, the upper wall region definingthe reservoir 32 is formed with an elongated recess 54 to accommodate anarm 60 of a lever o-r lever member 56 forming a component of means forcontrolling fuel ow from a supply into the reservoir or chamber 32. Thelever 56 is pivotally supported upon a pin 58, the short arm 62 of thelever 56 contacting the lower end of a fuel inlet valve member 64.

The valve member 64 is preferably of triangular or polygonalcross-section so as to facilitate flow of fuel past the body of valvemember 64. The valve member 64 is slidably disposed in a bore in afitting 66 which is threaded into a threaded bore formed in thecarburetor body 10. The boss portion 77 formed on the carburetor body isprovided with a threaded bore 68 adapted to receive a fitting (notshown) arranged to be connected with a fuel supply for feeding fuel intothe bore 70.

The bore 70 is in communication with a duct 72 with a 'port formed in avalve seat 76 disposed within the upper end of the threaded fitting 66.The annular valve seat 4 material, such as neoprene (chloroprene), Bunarubber or other material which is resistant to deterioration byhydrocarbon fuels. The valve body 64 is formed at its upper end with acone-shaped valve portion 77 adapted to ccoperate with the seat member76 to control fuel tiow from a supply into the reservoir or chamber 32.

The port or passage in the valve seat member 76 is of comparativelysmall diameter so that the effective fuel pressure acting against asmall area of the cone-Shaped valve portion 77 in order to provide forsensitive operation of the fuel inlet control mechanism. The carburetorbody 10 is formed with a recess adapted to accommodate an expansive coilspring 81 for biasing the lever 56 in a counterclockwise direction asviewed in FIGURE 4 for urging the valve 77 into contact with the seat76.

The head of the rivet 52 associated with the diaphragm 34 is always incontact with the lever arm 60 of the lever 56 when the carburetor s inoperation. When fuel is delivered through the orifice or outlet 42 intothe mixing passage by aspiration or reduced pressure in the mixingpassage 12, the diaphragm 34 is moved upwardly, causing pivotal movementof the lever 56 in a clockwise direction permitting the valve member 64to move downwardly and admit fuel through the port in the valve seat 76and thereby maintain fuel in the reservoir or chamber 32.

The arrangement of the invention is inclusive of a throttle actuated orcontrolled means for regulating the admission of fuel into the mixingpassage in proportion to the extent of opening of the throttle valve 26.A channel or duct is in communication with the supplemental reservoir 44or enlarged region adjacent the orifice 42. The carburetor body isformed with a bore 82 which is substantially parallel with the axis ofthe mixing passage 12.

The end region of the bore 82 is in communication with a bore 84 ofreduced diameter, the latter being in communication with the duct orpassage 80 as shown in FIG- URE 3. The bore 82 is in communication withthe reservoir or chamber32 by means of a channel or duct 83 shown inFIGURE 2 whereby fuel is admitted into the bore 82. If desired, an airbleed passage 86 may be provided between the air inlet 18 and the bore82 as shown in' FIGURE 3 for admitting air to the fuel prior to itsdelivery through the orifice 42.

Slidably disposed in the bore 82 is a fuel metering means or member 90formed with a tenon portion 92 of reduced diameter, the extremity 94 ofwhich is of tapered or needle-like shape forming a valve or meteringmedium restricting fuel flow from the bore 82 into the ducts 84 and 80into Ithe supplemental chamber 44.

, The taper on the portion 94 is of such angularity that movement of theAmember 90 in a left-hand direction as viewed in FIGURE 3 effects anincrease in the area surrounding the tapered portion in the restrictedpassage 84 to admit more fuel from bore 82 past the needle valve 94. Themember 90 is formed with a circumferential groove in which is disposed asealing ring 96 of resilient material to prevent leakage of fuel alongthe body portion of the member 90 and exclude foreign mat-ter.

The member 90 is biased in a right-hand direction as viewed in FIGURES 2and 3 under the influence of an expansive coil spring 98 disposedbetween the outer end of the member 90 and an abutment member orthreaded plug 100 which is threaded into the end region of the bore 82.The amount of spring pressure or bias exerted by spring 98 may beregulated by adjusting the relative position of the threaded abutment100.

The carburetor body 10 is formed with a boss portion e 102 provided witha longitudinal bore in which is slidably disposed a rod or shaft 104. Asshown in FIGURE 2, the longitudinal axis of movement of the shaft 104 isbelow the axis of the throttle supporting shaft 28.

The boss portion 29 adjacent the rod 104 is formed with a bore toreceive the end region of the rod.v The throttle member 76 is preferablyformed of resilient rubber-like '(5 shaft 28 is formed with a slot orrecess 105 adjacent the tig-'0083754 ndfof'the'rod 104, the base surface106 of the recess 105 forming a cam surface engaged by the adjacent endof the rbd 104 'as shown in FIGURE 2.

The opposite end region of the rod 104 is threaded as at 108 tothreadedly receive a member or block 109 which may be locked to theshaft or rod 104 by a locking nut 110. The member 109 extends downwardlyas illustrated in FIGURE 5, the distal end thereof being bifurcated orformed with an open ended slot 112, the furcations straddlng a portion114 of reduced diameter formed by a circumferential groove in the member90.

It will be apparent from FIGURE 2 that upon rotational movement of t-hethrottle supporting shaft 28 in a clockwise direction, the cam surface106 moves the rod or shaft 104 longitudinally and, through the medium ofthe interconnection between the member 109 and the member 90, the latterwill likewise be moved in a lefthand direction against the expansivepressure of the spring 98.

^ Asthe tapered needle portion 9,4 moves in a left-hand direction asvviewed in FIGURE 2, a passage of progressively increaseing area isprovided between the needle portion 94 and the wall of the bore 84 tofacilitate admission of an increased amount of fuel through the duct 80into the supplemental reservoir 44 for discharge through the orifice 42into the mixing passage where it is mixed with the air aspirated throughthe mixing passage under the influence of the movement of the enginepiston or pistons.

Thus the greater the opening position of the throttle 26,

the more fuel isl admitted for discharge into the mixing passage. Uponmovement of the throttle toward closed or idling position, the needleportion 94 is moved in a right-hand direction to proportionately reducethe amount f fuel owing past the needle into the mixing passage, theamount being suiicient to provide an idling mixture for the engine. Thethrottle 2-6 in engine idling position is not entirely closed so as toadmit a small amount of air for mixing with the reduced amount of fuelrequired for idling operation of the engine.

4The delivery of fuel into the mixing passage 12 only takes place underaspiration set up by operation of the engine whereby the carburetor willoperate or function in any angular or even inverted position. If theengine is inverted in idle position, the metering pin or needle 94 is ina position to permit the ilow of an amount of fuel necessary to maintainidling operation of the engine.

If the throttle is opened while the carburetor is in inverted position,-the metering pin or needle 94 is moved in a left-hand direction asviewed in FIGURES 2 and 3 to permit the passage of an increased amountof fuel proportionate to the amount of air moving through the mixingpassage to cause operation of the engine at the desired speed withoutooding of the fuel in the mixing passage. The initial or idling positionof the metering means 90 with respect to the rod 104 may be obtained byreleasing the locking -nut 110 and rotating the shaft 104 to effectadjustment of the metering needle 94.

It is to be understood that the abutment or cam surface106. formed onthe throttle shaft 2S may be of curved configuration to change or modifythe ratio of fuel to air, or the degree of taper of the metering needlevalve 94 may be changed to vary the fuel to air ratio. The spring 98serves several functions in the apparatus,v it exerts a biasing pressureto maintain the shaft 104 in contact with the cam surface 106 andassures positive control of the metering pin by eliminating lost motionthat may otherwise exist between the member 109 and the metering means90. The spring 98 also prevents vibration of the metering pin andfluttering of the throttle valve whereby the throttle and metering meansremain stable underA severe service conditions and vibration.

In. the arrangement illustrated in FIGURES l through i thev mixturecontrol. is obtained by a single adjustment and back bleeding throughthe nozzle under idling, condtionsis avoided. It is tobt-.understoodthat the air bleed passage 86 between the air inlet of the mixingpassage and the bore or chamber 82 may be omitted depending upon theoperating characteristics of the engine with which the carburetor isused.

FIGURES 6 through 9 illustrate a carburetor embodying another form ofthe invention. The arrangement in'- cludes a carburetor body which issimilar to the body 1t) shown in FIGURES l through 5 with certainmodifications. The body 1120 is formed with a mixing passage 122embodying a Venturi configuration 123 having a choke band or restrictedregion 124. The mixing passage 122 is provided with an air inlet 18'provided with a choke valve 22 mounted upon a rotatable shaft 20.

The mixing passage is provided with an air outlet 14 in which isdisposed a throttle valve 26' mounted upon a rotatable shaft 28 providedwith a manipulating 30. The carburetor body 120 is formed with a flangeportion 31' adapted to be secured to the crankcase of an engine of thetwo cycle type or to the intake manifold of an engine of the four cycletype.

The carburetor body is formed with a fuel reservoir or chamber 32 onewall of which is formed by a flexible diaphragm or membrane 34', a cover38' being provided for the diaphragm and having a vent opening 39 to'establish atmospheric pressure in the space 37'.

The fuel inlet control means illustrated in FIGURE 9 is substantiallythe same as that shown in the form f the invention illustrated inFIGURES l through 5. The head of the rivet S2' associated with thediaphragm 34' engages one arm of a lever 56' fulcrumed upon a piii 58',the other arm of the lever engaging a valve member 64 slidably mountedinv a hollow fitting 66' threaded into a bore in the body 120. A coneshaped valve por'-A tion 77 cooperates with a port in a valve seat 76'for controlling ow of fuel from a supply through a passage 70 and afitting (not shown) threaded into a bore in the boss portion 79'.

A coil spring 81 engages the lever arm in contact:` with the rivet head52' biasing the lever in a counterclockwise direction as viewed inFIGURE 9 to bias the valve 77 toward the seat 76. This form of theinvention invention includes a throttle controlled fuel metering meansof a character similar to that shown in FIGURES 1 through 5. A bore 82formed on the body 120 slidably' receives a metering means which isinclusive to a member 128 similar to the member 90 shown in FIGURE 2.

One end of member 128 is formed with a tenon portion 130 from whichextends a tapered metering valve or needle portion 132 the tenon portion130 extending in to a bore 134 in communication with the bore 82. The'metering needle 132 extends into a restricted passage 136 which is incommunication with an elongated chamber 138. The metering means 128 isnormally biased in a left-hand direction as viewed in FIGURE 7 under theinuence of an expansive coil spring 98 which abuts' an adjustablethreaded member 100.

The abutment 100 may be rotated to adjust the pressure of the spring 98upon the member 128. A sealing' ring 96 is disposed in a circumferentialgroove in the body portion of member 128 to prevent leakage of fuelalong the member and to prevent ingress of foreign par# ticles. Disposedin the region beneath the choke band 124 of the Venturi mixing passage122 is an auxiliary chamber or well 139 which is in communication with amain fuel discharge outlet or orifice 140 opening info the choke band124 of the Venturi 123.

Formed in the body 120 in a region adjacent the discharge region of theVenturi is an auxiliary chamber 142 which is in communication with thechamber 139 by means of a channel or passage 144. An idling oriice 146and a low speed orifice 148 in a wall of the mixing passage adjacent thedischarge region of the Venturi 123 are adapted to deliver fuel fromchamber 142 into the mixing passage for engine idling and low speedpurposes.

It should be noted that the idling orifice 146 is at acca-754 the engineside of the throttle valve 26so that when the latter is in nearly closedor idling position, fuel is discharged through the idling orilice 146under the iniluence of engine aspiration.

The orilices 146 and 148 are herein referred to as secondary orifices.When the throttle valve 26 is in partially open position, fuel may bedischarged from both orifices 146 and 148 depending upon extent ofopening of the throttle valve. The chamber 142 is isolated from thechamber 32 by means of a Welch plug 150. The lower end of the passage orchamber 139 is closed by means of a plug 141.

The bore 134 is in communication with the chamber or well 139 by meansof a duct 152. Fuel is conveyed from the chamber 32 through a passage orchannel 154 shown in FIGURE 7 into the elongated chamber or duct 138. Anair blew means for the fuel in the elongated chamber 13S is provided bya passage 156, one end of which is in communication with the air inletend of the mixing passage, the other end being in communication with thechamber 13S through a restricted passage 158 as shown in FIGURE 7.

Thus fuel is admitted into the chamber 138 through the passage 154 andair is admitted to the fuel in chamber 138 through the connecting airbleed passages 156 and 158 whereby a mixture of fuel and air is meteredor controlled by the needle valve 132 supplied to both the main orifice14) and the secondaryvoriiices 146 and 148. The metering means 128 iscontrolled by a cam associated with the throttle in the mannerhereinbefore described in reference to FIGURES l through 5.

A rod or shaft 104 is slidably mounted in the boss portion 102', one endof the rod 104 engaging the cam surface 106' formed by a recess 105' inthe throttle shaft as shown in FIGURE 7.

The opposite end of the rod 104 is threaded to receive a block or member160 similar to the member 109 shown in FIGURE which may be locked inadjusted position on the rod 104 by a locking nut 110. The block 160 hasa bifurcated portion 162 which straddles a reduced portion 164 formed inthe member 128.

Thus when the throttle shaft is rotated, the cam 106' effectslongitudinal movement of the rod 104', block 160 and the member 128carrying the metering needle 132 for adjusting the amount of fueladmitted to the supplemental chamber 139 for discharge through the mainorifice 140 or for discharge from the secondary orifices 146 and 148. Itshould be noted in this arrangement, that the single metering means orneedle 132 provides for the fuel adjustment for fuel delivered to all ofthe discharge orifices.

The operation of this form of construction is as follows: In initiallystarting the engine with which the carburetor is used, the throttle 26'is moved to open or partially open position and the choke valve 22 movedto closed position. Upon starting the engine the choke valve 22' isgradually opened as the engine warms up. In idling position the throttle26' is nearly closed and air ow through the passage is restricted sothat there is substantial subatmospheric pressure at the engine side ofthe throttle 26 causing fuel to be discharged through the idling orifice146.

When the carburetor is provided with the air bleed passage 156, air isadmitted into the elongated chamber 13S for mixing with the fuel movingpast the metering needle 136 thence into the passage 139 and through thepassage 144 into the chamber 142 so that an emulsion or mixture of fueland air is delivered from the idling orifice 146.

During this period little or no fuel is discharged from the low speedorifice 148 and additional air from the mixing passage may be bled intothe fuel through the main orifice 140.

As the throttle 26' is opened to a greater extent, the secondary or lowspeed oritice 142 comes intooperation 8 and deliversfuel'and air mixtureinto the mixing Passage in addition to that supplied by the idlingorifice 146.

During this operation some air may also be bled into the fuel in chamber139 from the mixing passage through the main orifice 140. As thethrottle is opened toa greater extent, the engine speed increases andhence a greater volume of air at high velocities moves through themixing passage. Under this high aspiration or differential pressure inthe mixing passage, fuel and air mixture is discharged from the mainorifice 140 and the delivery of fuel and air mixture through the idlingand low speed orifices 146 and 148 is substantially reduced.

As fuel is delivered into the mixing passage from any of the orifices,the diaphragm 34 is elevated effecting a tilting of the lever 56'permitting the valve member 6 4' to move away from the seat 76' to admitadditional fuel into the reservoir or chamber 32 to replenish the fueldelivered into the mixing passage.

As the throttle valve 26 is moved progressively toward open position,the cam surface 106 moves the rod 104' in a right-hand direction asviewed in FIGURE 7 withdrawing the metering needle or member 136 in aright-hand direction thereby increasing the passage area adjacent themetering needle 136 so that an increasing amount of fuel is admittedinto the chamber 139 for discharge through the orifice 140 or throughthe secondary orifices 146 and 143 dependent upon the extent of openingposition of the throttle 26'.

In this manner the ratio of fuel to air forming a combustible mixturemay be regulated and controlled and the fuel metered in a mannerenabling the operation of the carburetor in extreme angular and invertedpositions without liability of flooding fuel into the mixing passage asthe metering means regulates the fuel ow dependent upon engine speed orengine requirements.

The idling position of the metering needle 136 in the passage 132 may beadjusted by loosening the locking nut and rotating the shaft 104' tochange the relative position of the metering pin actuating block 160with respect to the cam surface 106'. In this form of carburetor orcharge forming apparatus the relatively movable metering needle 136controls the fuel or fuel emulsion supplied to both the main orifice andthe secondary orifices 146 and 148.

Another form of charge forming apparatus or carburetor of the inventionis illustrated in FIGURES 10 through 14. In this form the carburetorbody 10" is formed with a mixing passage 122" embodying a Venturi 123having a choke band 124". The arrangement is provided with a choke valve22" mounted on a shaft 20", and a throttle valve 26" mounted upon athrottle shaft 28". The construction includes a flexible diaphragm 34"which through the medium of a lever 56" controls an inlet valve member64" having a valve portion 77" cooperating with a seat 76" forregulating the ingress of fuel into the reservoir or chamber 32".

This form of the invention includes a throttle control metering pin ofsubstantially the same construction as illustrated in the form of theinvention of FIGURES 6 through 9. The throttle shaft is formed with acam or cam surface 106" which cooperates with a rod 104" to move a blockwhich controls the position of a metering means 128" slidable in a boreS2". The metering means 128 is provided with a metering needle or pin1-32" cooperating with a restricted passage 136" for metering orcontrolling fuel delivered into the mixing passage.

Fuel is admitted into an elongated chamber 138" from the reservoir orchamber 32" through a passage or duct 170. An air bleed for the fuel inthe elongated chamber 138" is provided by a duct 156" and a restrictedpassage 172 whereby air is admitted from the entrance of the Venturi inthe mixing passage into the chamber 138" and an emulsion of fuel and airdelivered past the metering needle 132". The metering means 128"` -is.Sacar-a4 svlidable in the bore 82" and is of the same construction alsillustrated in the form of the invention shown in FIG- URES 6 through 9.

The chamber 134 at the right side of the restriction 136, as viewed inFIGURE 10, is connected with a well o r supplemental chamber 139" bymeans of a channel or dnt 152". The fuel in the well 139" is deliveredinto the choke band 124" through the main fuel discharge orice or outlet140". In this form of the invention, the throttle controlled meteringneedle or pin 132" regulates the amount of fuel delivered through themain orifice 140". The fuel supply for the secondary orices or idlingand low speed orifices 146 and 148 is independent of the fuel suppliedto the main fuel discharge orifice 140".

'I he body is formed with the chamber 142" which is isolated from thechamber 32 by means of the Welch plug 150". Formed in the body 10" is atransversely extending bore 176 which forms an extension of an enlargedthreaded bore 178, the latter accommodates the threaded portion 179 of asupplemental fuel adjusting means 180. Formed on the end of the threadedportion 179 is a valve or metering needle 182 which extends into arestricted passage or channel 184 which. opens into 'the chamber or well142". d

'Ifhe fuel metering means 180 is formed with a knurled manipulating orfinger grip portion 186 and interposed between the manipulating portionor headl 4186 and a ledge provided by an enlarged bore formed in thebody 1.0'-is .l an expansive coil spring 1.88v which provides afijietipn component to retain the metering needle 182 in adjustedposition. Fuel is admitted. directly to the xbore 176 from the chamber32 through a duct or pas.-

age 190 shown in FIGURE 14. Means is provided for bleeding air into thefuel in the bore 176,.

shown in FIGURE 10 an air bleed passage 1 92 opens into the entrance ofthe Venturi as shown in FIG- URE 10 and is in communicationv with thebore 1 76 through a restriction 177 to admit air from the mixing passageinto the bore 176 for mixing with the fuel in the bore 176. Thus anemulsion or a mixture of fuel and air is provided in the bore 176 whichis delivered past the metering needle 182 into the well or reservoir142" for discharge through the secondary orifices 146" and 148".

The metering needle 182 provides a means for adiustably regulating orcontrolling the fuel and air mixtnre or air-bled fuel supplied to thewell 142 for the secondary orifices which is completely independent fromthe throttle controlled means for regulating the emulsion or fuel andair mixture delivered to the well 139 for discharge into the mixingpassage through the main ori- 140". Through this arrangement the fueland air supplied to the mixing passage through the secondary orificesmay be accurately controlled and the fuel: and air mixture deliveredthrough the main orifice accurately controlled by the throttle actuatedmetering means 12S".

The operation of the arrangement shown in FIGURES 10 through 14 isgenerally similar to the operation of the arrangement shown in FIGURES 6through 9 with the exception that the fuel delivered to the secondaryorifices 146" 4and 148" is regulated and controlled independently of thefuel delivered through the main orifice 140".

Another form of the charge forming apparatus or carburetor embodyingmeans is illustrated in FIGURES l through 2 0. This arrangementcomprises a carburetor body 2 00 formed with a mixing passage 202, thebody being formed with a flange 204. The flange 204 is formed withopenings 206 adapted to receive bolts or other means for vattaching thecarburetor to an engine crankcase or intake manifpld. The mixing passage202 is formed with an air inlet 207 in which is disposed a disk-typechoke valve 208 mounted upon a rotatable shaft 210 equipped' with amanipulating arm 212.

The body 200. is formedwithA a.- depending portion 214 throttlecontrolledfuel meteringwhich terminates inl a circular disk-like portion21d fashioned with a circular recess forming an unvented fuel chamber orreservoir 218. Extending across and lforming a wall of the chamber 218is a exible diaphragm 220, the periphery of which is preferablycoincident with the periphery of the disk-like portion 216. Disposedbetween the peripheral region of the diaphragm andthe portion 216 is anannular gasket 222.

Disposed beneath the diaphragm is a cover member 224, the peripheralregions of the cover member, dia.- phragm 229 and gasket 222 beingprovided with openings to receive securing bolts 226 which are threadedinto `suitable openings formed in the peripheral region of the disklilceportion 216. The cover member 224 is depressed at the central region toform a space 228 to facilitate movement of the diaphragm 220, a ventopening 230 being provided to establish atmospheric pressure in thespace 228 at all times.

The means for admitting fuel through a valved inlet into the reservoiror chamber 218 and the control means therefor shown in FIGURE 19 aresubstantially the same as the arrangement illustrated in the other formsof the invention. The head portion of a rivet 232 associated with thediaphragm engages one arm of a lever 234 which is of the sameconstruction as the lever 56 shown in FIGURE 4, the same being fulcrumedupon a pin 236. The other arm of the lever engages the body of a valvemember 238 the latter formed with a conicallyshaped valve portion 240which cooperates with a ported valve seat 242 held in a bore in thecarburetor body by means of a threaded fitting 244.

lFuel is admitted to a passage 246 formed in the carburetor body in thesame manner as described in connection with the other forms of theinvention. The lever 234 is biased for movement in a clockwise directionabout its' fulcrum 236 under the influence of an expansive spring 248.As fuel is discharged into the mixing passage, in a manner hereinafterdescribed, under the inliuence of reduced pressure in the mixingpassage, the diaphragm 220 is elevated as viewed in FIGURES l7 and 19pivoting the lever 234 in a counterclockwise direction as viewed inFIGURE 19 whereby the valve member 238 moves downwardly to permit fuelto ow through the port in the seat 242 past the valve portion 240 intothe reservoir 218.

The charge forming apparatus or carburetor shown in FIGURES 15 through20 embodies a piston or barreltype throttle means or valve which isassociated with a movable metering device or means for varying orregulating the rate of delivery or flow of fuel to the mixing passage inaccordance with opening and closing movements of the throttle. Thecarburetorbody 200 is formed with an upwardly extending generallycylindrical portion 250, the upper exterior region of which is threadedto receive a threaded cap 252. The portion 250 is provided with acircular cylindrical interior surface or bore 254 in which is slidablymounted a cyliudrically shaped throttle or throttle member 256 which maybe referred to as a.

piston-type throttle.

The upper portion of the throttle member 256 is provided With aninterior bore to accommodate an expansive coil spring 258 which normallybiases the throttle 256 tow-ard closed position. LIn this form ofconstructiom the throttle valve 256 is preferably manually operated bymeans of a iiexible cable or wire 260, the lower end ofv which is formedwith an enlargement or anchor 262 which engages in a recess 264 formedin the throttle valve 256 as shown in FIGURE' 18. The throttle member256 is associated with -a fuel metering means or pin 266 which isfashioned with a tapered fuel metering pottion 268 arranged to extendinto a fuel discharge passage 270 in the manner shown in FIGURE 17.

The upper end region of the movable metering pin 266 is formed with aplurality of peripheral recesses 272 and a circulaislotted disk 274 maybe selectively received' in one ofthe recesses 272 to establish aconnection between 11 4the metering pin and the valve 256. The method ofengaging the disk 274 with the metering means 266 is particularlyillustrated in FIGURES 17 and 20. The disk 274 seats against the bottomof the bore in the throttle member 256 and the end of the spring 258engages the disk to hold the same in proper relation for movement withthe throttle member 256.

It will be noted that as the tapered portion 268 is progressivelyreduced in a downward direction as viewed in FIGURES 17 and 20,elevation of the metering pin 266 by movement of the throttle upwardlyeffects a progressive increase in the area of the annular passage 270surrounding the tapered portion 268 of the metering means to admit aprogressively increasing amount of fuel through the annular fueldischarge outlet 276.

The cap member 252 is formed with a tenon portion 278 .which isinteriorly threaded to accommodate the threaded portion of a ferrule 280through which extends the throttle control wire or cable 260. Theferrule 280 is provided with a portion 282 bored to accommodate theextremity of a flexible sheath or guide 284 which encloses the throttleoperating cable 260. The opposite end region of the cable 260 may beprovided with a manipulating knob (not shown) or other means for movingthe cable lengthwise to control the position of the throttle 256.

The ferrule 280 is secured in position by means of a lock nut 290. Asshown in FIGURE 18 the throttle valve member 256 is formed with alongitudinal recess or slot 292 which accommodates a tenon 294 formed ona member 296 threaded into a bore contained in the wall of thecarburetor body adjacent the throttle. The member 296 is provided with ahead portion 298 slotted to accommodate a tool for aixing and removingthe member 296. The tenon portion 294 cooperates with the lengthwiseslot 292 in the throttle member to prevent rotation of the throttlemember.

Formed in the depending portion 214 of the carburetor body is a threadedbore which accommodates a fitting 309 provided with a restricted passage302 opening into a passage or duct 270. When the throttle is in nearlyclosed or idling position, the metering pin 266 extends into the passage270 so that the larger cross-sectional area of the tapered portion 268decreases the effective area of the passage to thus reduce the fuel flowto that required for engine idling purposes.

The engine idling position of the metering pin 268 may be adjusted orvaried with respect to the throttle valve 256 by changing the relativeposition of the ferrule 280 with respect to the cap member 252. When itis desired to change the idle adjustment, the lock nut 290 is releasedand the threaded ferrule 280 rotated to move the same lengthwise of thecap 252 which, through the medium of the sheath 284 engaging a fitting(not shown) at the opposite end of the sheath eiects an adjustment ofthe cable 260 lengthwise so as to thereby change the initial or idlingposition of the throttle member 256 in the mixing passage.

In certain installations it may be desirable to provide an air bleed forthe fuel in the passage or duct 270. As shown in FIGURE 17 an air bleedpassage 308 may be provided having a restricted portion 310 foradmitting air from the inlet end 267 of the mixing passage into thepassage 27 0 for mixing with the fuel prior to its discharge through theoutlet or orifice 276 of the passage 270. It is to be understood thatthe arrangement may be utilized in certain installations without the useof the air bleed 308.

The annular recesses 272 fashioned in the upper end o f the meteringmember 266 are provided so that the initial position of the metering pinwith respect to the passage 270 may be adjusted to change the ratio offuel to air to secure efiicient operation in various temperatureenvironments or seasonal changes.

In the operationof this form of construction it will be apparent that anopening movement of the throttle 256,that'is, an upward movement asviewed in FIGURE 17 provides for a progressively enlarging passage ofair into the engine and, through the medium of the tapered meteringmeans 268, a progressively increased amount of fuel is delivered intothe restricted passage formed between the end region of the throttlemember 256 and the opposite wall portion of the mixing passage.

Thus as the engine speed increases or decreases, dependent upon theposition of the throttle 256, a proportionate increase or decrease inthe amount of fuel delivered into the increasing or decreasing amount ofair moving through the mixing passage is obtained. It will b'e apparentin this arrangement that all fuel requirements for idling, low speed andhigh speed operation are provided from the single passage 270 and outlet276 as permitted by the relative position of the tapered portion 268 inthe passage 270 in accordance vwith the amount of air moving throughlthe mixing passage.

The charge forming apparatus illustrated in FIGURES -15 through 20 hasparticular utility for use with engines for powering motorcycles,bicycles and other kindred uses where the carburetor may be subjected tovibration due to road irregularities. Vibration does not appreciablyimpair or affect the functioning of the diaphragm as fuel isadmitted tothe mixing passage solely through engine aspiration.

While the forms of the invention illustrated in the drawings embody anelement associated directly with throttle valve for actuating the fuelmetering means, it is to be understood that other means responsive tochange in the position of the throttle valve may be employed to actuatethe fuel metering means for varying the fuel ow through the fuelchannel.

. It is apparent that, Within the scope of the invention, modificationsand different arrangements may be made other than as herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

I claim: v

l. In combination, charge forming apparatus including a casing formedwith a mixing passage, a throttle valve movably disposed in the mixingpassage, a fuel chamber formed in the casing, a ilexible diaphragmforming a wall of the fuel chamber, the diaphragm being movable inwardlyupon depletion of the fuel within the chamber, a fuel inlet for the fuelchamber, valve means for the fuel inlet, means actuated by movement ofthe diaphragm for controlling said fuel inlet valve means, a fueldischarge orifice opening into the mixing passage, a fuel duct betweenthe orifice and the fuel chamber, the throttle valve mounted on arotative shaft extending transverse of the mixing passage, said shafthaving a por# tion with a cam surface thereon positioned outside of themixing passage and in the casing, a fuel metering assembly comprising areciprocating fuel metering member movable to vary fuel ow through thefuel duct, a reciprocable rod mounted inthe casing in a directiongenerally normal to the throttle valve shaft and having one,

end which engages the cam surface, the reciprocable fuel metering memberbeing mounted in the casing in a bore disposed parallel to thereciprocable rod and having a tapered forward portion which ispositioned within the duct, a'connecting member connected to thereciprocable rod at its other end and engaging the fuel metering memberso that movement of the reciprocable rod will change the position of themetering member, a spring mounted in the casing which engages a rearportion of the meter ing member to hold the rod against the cam surfaceand assure position control of the metering member, and the connectingmember threadedly engaging the reciprocable rod whereby rotation of thereciprocable rod with respect tothe connecting member will adjust theposition of the recprocable rod with respect to the metering member.

2. The charge forming apparatus of claim 1 wherein a threaded plug ismounted in the casing in line with the rear of the fuel metering memberand engaging said spring member whereby pressure on the metering membermay be varied.

References Cited in the le of this patent UNITED STATES PATENTS

